Would earth rods in t'ground work like any other resistor? Ie - stick one in and get a 160ohm reading. Stick two in and that should halve. Stick 3 and third, etc?
Might be interesting reading sometime un pages 36 to 40 The SWA will need to be earthed at source perhaps 100ma time delayed. Perhaps another option is to get the house made into PME & isolate the earth on the swa at the far end http://www.weschler.com/_upload/sitepdfs/techref/gettingdowntoearth.pdf
You woud still need to RCD protect the submain, as I said, with a 100 or 300mA time delay. RCBO at 30mA ony for circuits that require it.
As lectrician said 160 ohms is fine, Maybe bang in another rod near the location of the original and link them, then 100mA TD on the submain or 300ma. If the Bedroom / Kitchen conversion is going to be rented or used a separate dwelling then I would consider having it on its own rod if not then nothing wrong with having the whole system on the existing rods, either way you will definitely need the submain on a 100ma TD minimum
I'm assuming that driving in at an angle would allow more rod length to driven in before it hits the bedrock - as the ground tends to get much harder to penetrate the deeper you go as with founds
Dig a large pit and use copper plates with large surface area . I've used an old copper water tank cut in half and splayed and layed flat with inside of tank facing up to retain water when it rains that way it's got better chance to give you a good earth
I used to do a lot of classic car MIG welding and there was a copper spray which was used to improve connectivity and applied on the treated steel before welding. I wonder if such an item exists to help in this case? Cheers Fats
I find you get a better cross section of soil type, rather than going deep. More likely to find something suitable at an angle.
I beg to differ Lec. Straight down or at an angle - the depth is the same speaking on a relative basis (ie 2ft in at an angle, or 2 ft down - the rod still goes into terra firma the same amount). The chances of hitting soil with an appreciable composition differential when driving at an angle instead of going straight down - is very remote indeed. That's my opinion anyway..
All you have got to do is get the rod in as far as possible and stick bentonite round it - and then next to the rod dig a trench/hole and sling in a flattened DHW copper cylinder (like that chap suggested) after of course solidly connecting said to a piece of 16mm which also goes onto t'earth rod. Before filling the hole wet everything down, and keep wetting t'backfill. Ra will be the bees knees..